1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
|
#include <mbgl/gl/headless_backend.hpp>
#include <mbgl/util/logging.hpp>
#include <cassert>
#include <GL/glx.h>
namespace mbgl {
// This class provides a singleton that contains information about the configuration used for
// instantiating new headless rendering contexts.
class GLXDisplayConfig {
private:
// Key for singleton construction.
struct Key { explicit Key() = default; };
public:
GLXDisplayConfig(Key) {
if (!XInitThreads()) {
throw std::runtime_error("Failed to XInitThreads.");
}
xDisplay = XOpenDisplay(nullptr);
if (xDisplay == nullptr) {
throw std::runtime_error("Failed to open X display.");
}
const auto* extensions = reinterpret_cast<const char*>(
glXQueryServerString(xDisplay, DefaultScreen(xDisplay), GLX_EXTENSIONS));
if (!extensions) {
throw std::runtime_error("Cannot read GLX extensions.");
}
if (!strstr(extensions, "GLX_SGIX_fbconfig")) {
throw std::runtime_error("Extension GLX_SGIX_fbconfig was not found.");
}
if (!strstr(extensions, "GLX_SGIX_pbuffer")) {
throw std::runtime_error("Cannot find glXCreateContextAttribsARB.");
}
// We're creating a dummy pbuffer anyway that we're not using.
static int pixelFormat[] = { GLX_DRAWABLE_TYPE, GLX_PBUFFER_BIT, None };
int configs = 0;
fbConfigs = glXChooseFBConfig(xDisplay, DefaultScreen(xDisplay), pixelFormat, &configs);
if (fbConfigs == nullptr) {
throw std::runtime_error("Failed to glXChooseFBConfig.");
}
if (configs <= 0) {
throw std::runtime_error("No Framebuffer configurations.");
}
}
~GLXDisplayConfig() {
XFree(fbConfigs);
XCloseDisplay(xDisplay);
}
static std::shared_ptr<const GLXDisplayConfig> create() {
static std::weak_ptr<const GLXDisplayConfig> instance;
auto shared = instance.lock();
if (!shared) {
instance = shared = std::make_shared<GLXDisplayConfig>(Key{});
}
return shared;
}
public:
Display* xDisplay = nullptr;
GLXFBConfig* fbConfigs = nullptr;
};
class GLXBackendImpl : public HeadlessBackend::Impl {
public:
GLXBackendImpl() {
// Try to create a legacy context.
glContext = glXCreateNewContext(glxDisplay->xDisplay, glxDisplay->fbConfigs[0],
GLX_RGBA_TYPE, None, True);
if (glContext && !glXIsDirect(glxDisplay->xDisplay, glContext)) {
Log::Error(Event::OpenGL, "failed to create direct OpenGL Legacy context");
glXDestroyContext(glxDisplay->xDisplay, glContext);
glContext = nullptr;
}
if (glContext == nullptr) {
throw std::runtime_error("Error creating GL context object.");
}
// Create a dummy pbuffer. We will render to framebuffers anyway, but we need a pbuffer to
// activate the context.
int pbufferAttributes[] = { GLX_PBUFFER_WIDTH, 8, GLX_PBUFFER_HEIGHT, 8, None };
glxPbuffer =
glXCreatePbuffer(glxDisplay->xDisplay, glxDisplay->fbConfigs[0], pbufferAttributes);
}
~GLXBackendImpl() final {
if (glxPbuffer) {
glXDestroyPbuffer(glxDisplay->xDisplay, glxPbuffer);
}
glXDestroyContext(glxDisplay->xDisplay, glContext);
}
gl::ProcAddress getExtensionFunctionPointer(const char* name) final {
return glXGetProcAddress(reinterpret_cast<const GLubyte*>(name));
}
void activateContext() final {
if (!glXMakeContextCurrent(glxDisplay->xDisplay, glxPbuffer, glxPbuffer, glContext)) {
throw std::runtime_error("Switching OpenGL context failed.\n");
}
}
void deactivateContext() final {
if (!glXMakeContextCurrent(glxDisplay->xDisplay, 0, 0, nullptr)) {
throw std::runtime_error("Removing OpenGL context failed.\n");
}
}
private:
const std::shared_ptr<const GLXDisplayConfig> glxDisplay = GLXDisplayConfig::create();
GLXContext glContext = nullptr;
GLXPbuffer glxPbuffer = 0;
};
void HeadlessBackend::createImpl() {
assert(!impl);
impl = std::make_unique<GLXBackendImpl>();
}
} // namespace mbgl
|
